Shader "Study/Chapter4/Alpha Blend Cull"
{
	Properties
	{
		_MainTex ("Main Tex", 2D) = "white" {}
		_AlphaScale ("Alpha Scale", Range(0, 1)) = 1
		_Color ("Color Tint", Color) = (1, 1, 1, 1)
		[Toggle]_OpenZWrite("ZWrite",int) = 0
		
	}
	SubShader
	{
		Tags {"Queue"="Transparent" "RenderType"="Transparent" }

		
		Pass
		{

			Tags { "LightMode"="ForwardBase" }
			
			Cull Front

			ZWrite Off
			Blend SrcAlpha OneMinusSrcAlpha	

			CGPROGRAM
			#pragma vertex vert
			#pragma fragment frag

			#include "UnityCG.cginc"

			struct appdata
			{
				float4 vertex : POSITION;
				float2 uv : TEXCOORD0;
			};

			struct v2f
			{
				float2 uv : TEXCOORD0;
				float4 vertex : SV_POSITION;
			};

			fixed4 _Color;
			sampler2D _MainTex;
			float4 _MainTex_ST;
			fixed _AlphaScale;

			v2f vert (appdata v)
			{
				v2f o;
				o.vertex = UnityObjectToClipPos(v.vertex);
				o.uv = TRANSFORM_TEX(v.uv, _MainTex);
				return o;
			}

			fixed4 frag (v2f i) : SV_Target
			{
				fixed4 col = tex2D(_MainTex, i.uv);
				col.rgb = col.rgb * _Color.rgb;
				// 通过面板参数，控制透明度
				return fixed4(col.rgb,col.a * _AlphaScale);
			}
			ENDCG
		}

		Pass
		{

			Tags { "LightMode"="ForwardBase" }
			
			Cull Back

			ZWrite Off
			Blend SrcAlpha OneMinusSrcAlpha	

			CGPROGRAM
			#pragma vertex vert
			#pragma fragment frag

			#include "UnityCG.cginc"

			struct appdata
			{
				float4 vertex : POSITION;
				float2 uv : TEXCOORD0;
			};

			struct v2f
			{
				float2 uv : TEXCOORD0;
				float4 vertex : SV_POSITION;
			};

			fixed4 _Color;
			sampler2D _MainTex;
			float4 _MainTex_ST;
			fixed _AlphaScale;

			v2f vert (appdata v)
			{
				v2f o;
				o.vertex = UnityObjectToClipPos(v.vertex);
				o.uv = TRANSFORM_TEX(v.uv, _MainTex);
				return o;
			}

			fixed4 frag (v2f i) : SV_Target
			{
				fixed4 col = tex2D(_MainTex, i.uv);
				col.rgb = col.rgb * _Color.rgb;
				// 通过面板参数，控制透明度
				return fixed4(col.rgb,col.a * _AlphaScale);
			}
			ENDCG
		}
	}
}
